This invention relates to encapsulation. More particularly the invention relates to a method for producing dry, particulate, encapsulated materials which tend to retain their original physical and chemical properties during processing and storage.
It is well known that certain natural and synthetic materials undergo a change in their chemical and/or physical properties when exposed to heating, auto-oxidative, or humid conditions. For example, aromas, flavors, vitamins, and the like are known to rapidly deteriorate upon exposure to the atmosphere. Flavors, in particular, are subject to changes in properties since they are commonly used in food products which are prepared by processes employing elevated temperatures.
Other processes encapsulate particles by employing oil-in-water or water-in-oil emulsions which are spray dried to dehydrate. In some cases a pre-drying operation is performed to prevent chemical oxidative deterioration during dehydration but, in any event, such processes are involved and expensive. Furthermore, in most cases the encapsulating films are too thin to preserve the original qualities of the particles, particularly volatile aromas or flavors, which become somewhat altered and diminished over relatively short periods of time.
U.S. Pat. No. 2.088,622 describes a method for preparing flavoring materials by constituting the flavorings in an aqueous emulsion and drying the emulsion either in a vacuum dryer, by spray drying, or by adding a dehydrating agent thereto. This patent describes the formation of a film around the emulsoid by the dehydrating agent but since the agents disclosed produce only friable coatings, they are readily cracked, permitting degradation of the flavoring materials. Thus, such materials have a relatively short shelf-life and tend to form undesirable clumps of the materials or glommules.